1. Field of the Invention
The present invention relates to a communication apparatus, in particular a communication apparatus including a spread spectrum clock generator and a PWM circuit, and to a signal processing method of the communication apparatus.
2. Description of the Related Art
There has been recently increased cases of employing a spread spectrum clock generator (hereinafter may be abbreviated as “SSCG”) as a measure against Electromagnetic Interference (EMI).
The SSCG lowers a peak value of a frequency spectrum of a clock signal by slightly changing a frequency of the clock signal (i.e., a basic frequency). Thus, a radiation noise can be reduced by employing the SSCG.
Conventionally, various controls are executed using a Pulse Width Modulation (PWM) circuit. The PWM circuit controls a ratio of time lengths of On- and Off-states of, e.g., a switch by changing a duty (i.e., a duty ratio) of a pulse wave in a predetermined cycle. The PWM circuit produces the pulse wave on the basis of a modulated clock signal in which the frequency is modulated.